kernel-netlink: Add options to enable parallel Netlink queries explicitly

As under vanilla Linux the kernel can't handle parallel dump queries and returns
EBUSY, it makes not much sense to use them. Disable parallel queries by default
to basically restore original behavior, improving performance.

1 files changed, 18 insertions, 5 deletions

diff --git a/src/libhydra/plugins/kernel_netlink/kernel_netlink_shared.c b/src/libhydra/plugins/kernel_netlink/kernel_netlink_shared.c
index 2875436c6..ba3b17e23 100644
--- a/src/libhydra/plugins/kernel_netlink/kernel_netlink_shared.c
+++ b/src/libhydra/plugins/kernel_netlink/kernel_netlink_shared.c
@@ -75,6 +75,11 @@ struct private_netlink_socket_t {
 	 * Number of times to repeat timed out queries
 	 */
 	u_int retries;
+
+	/**
+	 * Use parallel netlink queries
+	 */
+	bool parallel;
 };
 
 /**
@@ -290,7 +295,8 @@ static status_t send_once(private_netlink_socket_t *this, struct nlmsghdr *in,
 
 	while (!entry->complete)
 	{
-		if (lib->watcher->get_state(lib->watcher) == WATCHER_RUNNING)
+		if (this->parallel &&
+			lib->watcher->get_state(lib->watcher) == WATCHER_RUNNING)
 		{
 			if (this->timeout)
 			{
@@ -450,7 +456,10 @@ METHOD(netlink_socket_t, destroy, void,
 {
 	if (this->socket != -1)
 	{
-		lib->watcher->remove(lib->watcher, this->socket);
+		if (this->parallel)
+		{
+			lib->watcher->remove(lib->watcher, this->socket);
+		}
 		close(this->socket);
 	}
 	this->entries->destroy(this->entries);
@@ -461,7 +470,8 @@ METHOD(netlink_socket_t, destroy, void,
 /**
  * Described in header.
  */
-netlink_socket_t *netlink_socket_create(int protocol, enum_name_t *names)
+netlink_socket_t *netlink_socket_create(int protocol, enum_name_t *names,
+										bool parallel)
 {
 	private_netlink_socket_t *this;
 	struct sockaddr_nl addr = {
@@ -483,6 +493,7 @@ netlink_socket_t *netlink_socket_create(int protocol, enum_name_t *names)
 							"%s.plugins.kernel-netlink.timeout", 0, lib->ns),
 		.retries = lib->settings->get_int(lib->settings,
 							"%s.plugins.kernel-netlink.retries", 0, lib->ns),
+		.parallel = parallel,
 	);
 
 	if (this->socket == -1)
@@ -497,8 +508,10 @@ netlink_socket_t *netlink_socket_create(int protocol, enum_name_t *names)
 		destroy(this);
 		return NULL;
 	}
-
-	lib->watcher->add(lib->watcher, this->socket, WATCHER_READ, watch, this);
+	if (this->parallel)
+	{
+		lib->watcher->add(lib->watcher, this->socket, WATCHER_READ, watch, this);
+	}
 
 	return &this->public;
 }